Abstract Neuronal communications requires the availability of synaptic vesicles for neurotransmitter release. During his postdoctoral study, Dr. Jorquera demonstrated that complexin, a small cytosolic protein that binds the vesicle fusion complex, regulates vesicle availability in Drosophila, as well as vesicle trafficking between functional pools of synaptic vesicles. This is an exciting finding because it suggests a novel role for complexin in addition to its well defined function in the final steps of exocytosis. Because complexin dysfunction has been widely implicated in human diseases, including schizophrenia and Huntingtons, as well as cognitive dysfunction in the cortex and hippocampus, there is an important need to define the role of complexin in vesicle pool dynamics and in short-term plasticity. Defining the biological role of vesicle cycling in neural plasticity and complexin regulation in the brain would represent a fundamental advance in our understanding of the biology of the synapse and neuronal communication. This is the focus of Dr. Jorquera's application. Dr. Jorquera is a proficient electrophysiologist who is also experienced in live confocal imaging, and the proposal strongly relies on these techniques. Further, Dr. Jorquera will be mentored by Dr. Wu from the University of Iowa, who is a distinguished scientist and a recognized expert in Drosophila genetics. Dr. Jorquera's project also takes advantage of the Electron Microscopy Research Core, which is a part of the present application. The project will enable the Jorquera lab to utilize multidisciplinary approaches and develop an independent line of research focused on a highly important question of dynamic complexin functioning in nerve terminals. As such, the project aims to advance the professional development of a junior faculty from an underrepresented group and establish a strong neurophysiology lab at UCC, led by a dynamic promising PI, which would combine powerful multidisciplinary experimental approaches and thus serve to further promote scientific standards in Puerto Rico and overall diversity in the field of neuroscience.